Li-ion balancing charger

Now the market is full of chargers. Automatic and not, with the measurement of capacity and without it. Most chargers are universal and can charge elements of any chemistry. Lithium-ion and lithium-polymer are increasingly being used in different devices. Not so long ago I remodeled the screwdriver battery for 18650 lithium-ion cells. I charge it with a smart Turnigy charger. But this charger is not for everyone.

Will be required for assembly

Decided to assemble a simple charger with a balance for lithium-ion. The charger has 3 identical independent channels. They can be charged from one element to three. If necessary, you can add any number of channels. I have three of them, that is, 3S or 11.1 volts. The case for the balancing charger is the case from the burned-out D-link router. If there is a possibility, take the case a little more, work very closely in it.

One of the main component is the power supply of each channel.Their role is performed by the charger boards of the tablets, with a 5 volt output and a current of 1 ampere (or you can buy it on Ali Express - a 5 V 1 A switching power supply).

Charge controllers are boards from China - a charge controller for a 18650 battery. For each channel, its own controller. I have a board without protection, but in this case it is not needed. You can use controller boards with connectors, I have two of them missing, removed for other projects. The price of these modules is cheap. If you are working on reworking devices on lithium-ion and lithium-polymer, then these controllers are irreplaceable.

Making a balancing charger

Charge controller boards need to be soldered to the outputs of charge cards. It is possible and separately. I soldered to thick wires from the power cable, so the design is more rigid.

On the charge controller boards there are LEDs that indicate the charge and the end of the charge. They need vypayat. Instead they will be ordinary LEDs, of different colors.They will be attached to the windows where the router's LEDs blinked before.

Soldered wires from the old computer's hard-disk cable to the LEDs. If there are LEDs with a common anode (plus), then it is better to apply them. I did not have such, applied what is.

In place of the old LEDs, solder the cables with LEDs. In the photo I have a green LED for 3 mm. I had to replace them, they turned out to be burned, I didn’t check it before unzipping.

For the back panel, you need to cut out the overlay. In it we make cuts under the power switch and the output connector for 4 pins. Connector removed from the old hard drive. You can use any, for the required number of pins, with a current of 1-2 Amperes. The switch removed from the old computer power supply. Tighten the cover plate on two screws for rigidity.

Glue the output connector on epoxy glue or soda with super glue.I pasted it for speed with one and the other. Charge board with controllers, glued to thermo glue. But before fixing, I soldered network wiring.

One of the network wiring, solder to the switch. The second, directly to the second wire of the power cord.

Now we glue the LEDs. I glued thermo glue, you can soda with super glue.

Unsolder the output jumpers. Plus the first controller to the first leg of the output connector. Minus it on the second leg and connect with the plus of the second controller. And so on.

Twist the case and set it aside.

Make a wire for this charger. Apply two pieces of wire from a computer power supply.Soldered in order from the first contact of one connector to the contact of the second.

Connecting the charger to the screwdriver's battery (Alteration of the screwdriver's battery to lithium). A red LED indicates an ongoing charging process. At the end of the charge, the green LED lights up. Accordingly, the icons on the case light up: Wi-Fi, the second and fourth computers.

This is how we got this charger. Costs are minimal, and the benefits are great. This device can be charged for assembling on lithium-polymers, those that use modellers in their vehicles. The main thing is to make the correct charging wire.